Blower Motor Switch: Testing and Inspection

WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, REFER TO AIR-BAGS BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIR-BAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

Front
1. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Remove the heater-A/C control from the instrument panel. See Heater-A/C Control Replacement for the procedures. Check for continuity between the ground circuit (Z1V) cavity of the heater-A/C mode control wire harness connector and a good ground. There should be continuity. If OK, go to Step 3. If not OK, repair the open circuit to ground as required.
2. With the heater-A/C control wire harness connector unplugged, place the heater-A/C mode control switch knob in any position except the Off position. Check for continuity between the two ground circuit terminals in the mode switch receptacle of the heater-A/C control. There should be continuity. If OK, go to Step 4. If not OK, replace the faulty heater-A/C control unit.
3. Check for continuity between the ground circuit (C 72) cavities of the heater-A/C mode control wire harness connector and the heater-A/C blower speed switch wire harness connector. There should be continuity. If OK, go to Step 5. If not OK, repair the open circuit as required.
4. Check for continuity between the ground circuit (C 72) terminal and each of the blower motor driver circuit terminals in the blower speed switch receptacle of the heater-A/C control as you move the blower motor switch knob to each of the four speed positions. There should be continuity at each driver circuit terminal in only one blower motor switch speed position. If OK, test and repair the blower driver circuits between the heater-A/C control blower speed switch wire harness connector and the front blower motor resistor or the front high speed blower motor relay as required. If not OK, replace the faulty heater-A/C control unit.

Rear
1. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Remove the accessory switch plate from the instrument panel. Refer to Accessory Switch Plate in the Removal and Installation Instrument Panel, Gauges and Warning Indicators/Instrument Panel for the procedures. Check for continuity between the ground circuit cavity of the rear blower motor switch wire harness connector and a good ground. There should be continuity. If OK, go to Step 3. If not OK, repair the open circuit to ground as required.
2. With the rear blower motor switch wire harness connector unplugged, place the rear blower motor switch knob in any position except the Off position. Check for continuity between the ground circuit terminal and each of the blower motor driver circuit terminals of the rear blower motor switch as you move the blower motor switch knob to each of the three speed positions. There should be continuity at each driver circuit terminal in only one blower motor switch speed position. If OK, test and repair the rear blower driver circuits between the rear blower motor switch wire harness connector and the rear blower motor resistor or the rear high speed blower motor relay as required. If not OK, replace the faulty rear blower motor switch.